Alpine's music doesn't instantly present itself as Tiny Desk material: The Australian sextet crafts busily impeccable pop music with a danceable sway, prominent synths and the charming shared lead vocals of Phoebe Baker and Lou James. That's a lot of ingredients to strip down to a semi-acoustic set in the NPR Music offices; there's virtually no margin for error.

Thankfully, the two women at the band's heart possess gorgeously interlocking, harmony-intensive voices that require no sweeteners. Alpine's debut album, the brightly catchy A Is For Alpine, is a high-gloss studio production, which only helps make this four-song set — recorded at 9 o'clock at night to kick off an after-hours party on a nearby NPR roof deck — an essential companion piece. Taken together, the album and this relentlessly engaging performance form a charm offensive that's awfully easy to love.